Just recently about adjustable floors no one heard, they could only grin when they heard such a phrase. However, today everyone is talking about them, studying them and even trying to install them without the involvement of expensive hired workers.
We will lift the veil of secrecy for all those who have never heard of this type of flooring by providing necessary information in this article, and we will tell you how to make adjustable floors.
Advantages of adjustable coverings
The installation of adjustable floors has received Lately widespread in construction, especially in the reconstruction or repair of old buildings.
The adjustable floor system has gained such popularity because:
- Having a low weight, it can be used for floors with low bearing capacity. Installation of an adjustable floor allows you to raise the level of coverage to the desired level, without constructing a heavy concrete structure or house.
- Due to its perfectly flat surface, it is suitable as a base for almost any type of finishing coating, be it parquet, laminate, linoleum or ceramic tiles. In this case, no additional procedures are necessary when arranging the surface.
Note!
These are just the main advantages for which this type of floor is famous; in terms of technical indicators, it is also a level higher than all available options.
Why choose self-regulating floors
The following should also be added to the main advantages of this type of flooring:
- Self-adjusting floors are easy to make with your own hands. One person can easily cope with work in a room of 20-25 m2 in one day.
- The absence of “wet” processes eliminates dust and dirt and significantly reduces repair time. You don't have to wait for the base to dry before you start painting. next stage works
- In the underground space of such a system the following are possible:
- Installation of additional hydro-, sound- and thermal insulation.
- Laying utility lines.
- Heated floor equipment, both water and electric.
- Since wooden joists are located above the base of the floor (not on the concrete itself), the lumber is protected from rotting and destruction.
For your information!
However, this does not mean that the material should not be treated with antiseptics.
- High levels of strength and noise insulation.
- If the work technology is followed, the self-regulating heated floor of an apartment or house will last you up to 50 years.
Types of adjustable floors
Features of the technology for constructing self-regulating floors divide them into two types:
- Adjustable logs.
- Adjustable plates.
Let's talk about how to make an adjustable floor on joists.
In fact, the installation of adjustable floors can be divided into two stages:
- Installation of adjustable logs.
- Flooring rough coating.
Advice!
The material for decking over adjustable joists should be selected based on the type of final covering.
Plywood is suitable for laminate or parquet.
If you plan to cover ceramic tiles or linoleum is better to use sheets moisture-resistant plasterboard, DSP or similar materials.
For those wishing to install wooden floors, Euro-boards (dry, planed and tongue-and-groove) will be useful.
Let's move on directly to the work on installing self-regulating floors on joists.
There are also two options here:
- Adjustable floor with stiletto heels.
- The same thing, only on the corners.
In principle, both options follow the same principle and differ only in the mechanism for regulating the lag. Let us describe in more detail the construction of the floor on adjustable joists using studs.
For work you will need the following materials:
- High-quality, dry, planed timber with a cross-section of 50x50 mm without knots.
- Regulating mechanisms (list for one set):
- M6 hairpin.
- Two washers.
- Two nuts.
- Anchor for adjustable floor.
For your information!
Can be purchased ready-made kits adjustable floor, including adjustment mechanisms and timber prepared for assembly.
Naturally, this will increase the final cost of adjustable floors.
Money issue
The approximate price for an adjustable floor is 20-25 dollars per one square meter. It should be noted that the cost of such a floor system for further tiling will be much more expensive than for laminate. This is due to the fact that more joists are laid under the tiles.
If you want to save money, all the components for adjustable floors can be purchased in bulk at any construction or hardware store, and the work can be done with your own hands.
Installation process of adjustable joists
To carry out work on installing a self-regulating floor you need:
- Construction level (great if you have laser equipment, but you can get by with ordinary equipment).
- Technique for drilling holes with drill bits for concrete and wood plus a feather drill.
- Hammer.
- Hacksaw or angle grinder (can be purchased for rent at a hardware store).
Now directly instructions for installing floors with adjustable joists:
- We lay out the bars on the base in increments of 30 cm (for subsequent covering with ceramic tiles) and 50 cm (for parquet and laminate). A distance from the walls is required, but no more than 2-3 cm.
- We drill holes for the pins in the bars at a distance of 50 cm from each other, with a diameter slightly larger than the diameter of the pin. Most often, a stud with a diameter of 6 mm is used, and for an 8 mm anchor we drill holes of the same diameter.
- Next, you should counterbore the lag, that is, use a feather drill to select a piece of wood at each hole with a depth equal to the thickness of the nut along with the washer. The diameter of the sample should exceed the diameter of the washer by 1-2 mm. This is necessary in order to recess the nut and washer flush with the top of the joist.
- After that, using a drill or hammer drill, we drill holes for the anchors in the concrete.
Advice!
It is better to do this directly through the holes in the bars, then there is a chance to minimize the possible mismatch of the pin with the prepared hole.
If you hit a concrete void or reinforcement while drilling, you should change the position of the stud.
- We drive the anchors into the floor carefully but firmly, and screw in the studs. We screw the nuts onto the studs at approximately the same level and put on a washer that will serve as support for the beam.
- After installing all the studs, we apply the joist. We put washers and nuts on top of the beam, without tightening them completely (just tighten them).
- At this stage, you should set the lag to the desired position, adjusting using a level. The adjustment is made using the two lower outer nuts. Then we tighten the nuts on the remaining studs and tighten the upper nuts.
- The remaining logs are installed in a similar way. The main task at this stage is to align all the logs so that their upper part is at the same level.
- After aligning and securing all the joists, we cut off the bolts for adjustable floors (unnecessary excess) with a grinder or a hacksaw.
- The third stage is filling the underground space with insulation, hydro- and sound insulation, and laying the necessary communications.
- The final stage is laying the rough floor covering with screws.
This completes the installation process of the self-regulating floor. You can then proceed with your chosen final finish.
None fundamental difference There is nothing in the technology of installing adjustable joists on corners, except that the regulating mechanism here is not studs. With this method, the bars are attached not to studs, but to corners rigidly fixed to the base of the floor.
Briefly the process looks like this:
- We lay out the bars and mark their location on the base of the floor.
- Using these marks, we fix the corners in increments of 50 cm. The height of the corner is selected according to the required floor level (slightly less than this value).
- Next, using a level, we set the logs.
Advice!
To give rigidity to the lags, the corners are secured on both sides in a checkerboard pattern.
- Then, as in the previous method, we install the flooring, taking into account the nature of further finishing.
Another feature when using corners is the need to accurately align the joists in level without possible adjustment after completion of work. Therefore, if the adjustable floor initially lies at an angle, then it will be possible to get rid of unevenness only with the help of pads for the finishing coating.
As for fastening elements, you should not purchase non-galvanized screws and bolts; high humidity can greatly affect their strength, which will affect the entire surface.
And finally, I would like to say that it is worth Special attention pay attention to the locations of anchors or screws for the corners. If the fastener is located next to a knot, then there is a high risk that the joist will soon (under load) crack in this place. Try to place fasteners in clean and level places, with a pitch of no more than 60 cm.
Conclusion
In the video presented in this article you will find Additional information on this topic." width="640" height="360" frameborder="0" allowfullscreen="allowfullscreen">
Conclusion
The process of installing an adjustable floor itself, as you understand, is not particularly difficult; all the work may be familiar to many. Your biggest concern should be quality. building materials used in this process. You should not save on this, as you will have to invest in repairs in the future.
In the video presented in this article you will find additional information on this topic.
Reading time ≈ 5 minutes
You can make adjustable floors instead of concrete screed. The main thing is to find out in advance all the features of such structures and their installation.
If you've ever done a major renovation, you know how difficult it can be to level the floor. The solution may be to install an adjustable floor. This is an affordable alternative to concrete screed, the creation of which will not require a lot of effort and will not take much time.
What is an adjustable floor?
In the past, floor coverings were laid on joists and concrete screed. Today, however, more and more builders are opting for adjustable floors. This is about rough field, made in the form of plywood flooring or logs. The height of the surface can be controlled using special stand blocks.
The essence of the design is to use 18 mm plywood sheets or wood logs. The support for one or the other is provided by rack-bolts made of wear-resistant plastic. By rotating around an axis, the bolts change the height of the plywood or joist, making it possible to accurately level subfloors. After the structure is leveled, the bolts are securely fastened to the base using dowel nails.
The base can be: beam (wooden) or concrete (with screed, hollow, monolithic). As a rule, moisture-resistant plywood is placed on the joists. Next - any floor covering (parquet board, parquet, etc.). In order to better understand what adjustable plywood or joist floors are, you should look at the photos and videos on our website.
It is most advisable to use the design in the following cases:
- It is necessary to level the floor covering finishing in the shortest possible time;
- It is necessary to raise or level the floors to a significant height (a concrete screed will require a month to lay. An adjustable floor can be installed in a couple of days);
- Space must be left for communication systems;
- It is planned to create a multi-level floor;
- New flooring needs to be done old building when conducting overhaul or create it in a new building.
Types and features
Lags
If you use adjustable supports and joists to create a subfloor, the structure will be able to rise by at least 5 cm. This height will allow you to find space for additional sound and heat insulation, as well as for any communication systems.
You can easily assemble a floor on adjustable joists with your own hands. The logs have technological holes, into which you will need to screw the rack-bolts. The logs themselves are installed on the base and secured to it using long self-tapping screws with dowels pre-hammered into them. After this, it is necessary to level the logs by tightening the stand-up bolts. And then lay the finished floor covering.
Choose adjustable floor joists and you can build a durable and robust construction, even if you work alone.
Plates
If for some reason you are not comfortable with adjustable joist floors, you can create a slab structure. The surface will rise by at least 3 cm.
IMPORTANT! In case of adjustable plywood there will be enough voids for various wires, not enough for large communications.
Several plywood sheets act as slabs. In the lower one, technical holes are made for the sleeve with internal thread. On one side, the bolt legs are secured to the base of the floor with self-tapping screws, and on the other, they are screwed into the bushing. To level the surface, you need to rotate the bolts.
Arguments against"
There are several disadvantages to adjustable floors that you should be aware of before deciding to install them:
- The floor will begin to creak. Even if every anchor and every screw in the system is high quality, this problem is not easy to avoid. Only a competent approach will help you deal with it: during installation, get rid of all the dust and dirt remaining after hammering in dowels and drilling holes. Before laying the second layer, thoroughly clean the first. Each nail must be driven to the maximum. Unfortunately, wood will in any case be deformed from the weight or humidity in the premises. Such a floor will certainly begin to creak;
- By raising the floor to a greater height, you will hear additional sounds in the future. For example, women's heels will sound like beating a drum. Additional sound insulation is required.
Arguments for"
The list of benefits is longer:
- Ease of installation. You can install the structure yourself within 24 hours;
- The adjustable floor is durable and reliable;
- The design allows for additional sound insulation of the premises from the outside;
- All communications can be safely and securely hidden from prying eyes In one place;
- You can set the horizontal level of the floor surface most accurately;
- The system is created from environmentally friendly materials;
- Even if the floor does not match by 15 cm, the situation can be corrected in a short time.
Selection of materials
We have already said that an adjustable floor is created in two stages:
- Installation of logs with movable supports;
- Arrangement of flooring.
Which sheets to choose? It depends on what the face covering is. If you want to lay parquet or lay laminated panels, use moisture-resistant plywood. If tiles or linoleum, choose moisture-resistant plasterboard sheets.
For wooden floor Experts advise using tongue-and-groove and smooth boards. The supports may be different, but their difference from each other lies only in the method of adjusting the height of the flooring - floors on corners or on studs.
Installing a wooden floor along joists on a concrete base is a common way to create a warm, well-ventilated structure that can serve fine coating when using tongue and groove boards or be an excellent basis for finishing facing material. At the stage of manufacturing such a floor, the question arises: what is the best way to attach the joists to concrete floor? This is what we will discuss in today’s material.
Despite the fact that the advantages of creating a flooring with joists rigidly fixed to the base are obvious, there are opponents of this method who claim that in this way the integrity and sound insulation of the room can be damaged due to the formation of acoustic bridges in the places where the fasteners are installed.
If the screed is destroyed during drilling, then this indicates its poor quality and should serve as a signal to dismantle it completely and fill in a new one. A high-quality screed does not change its integrity when holes are drilled in it using a drill.
Regarding sound insulation: a rigid structure transmits sound waves, but if you consider that between the lags insulation material, which dampens the sound, then this statement can be considered controversial. In addition, concrete is much denser than wood, and therefore the sound that is transmitted through the acoustic bridge to concrete base it won't reach the neighbors below.
One of the nuances wooden flooring along the joists there is the possibility of a squeak that can be heard even by the neighbors below. This occurs when structural elements (beams, joists and fasteners) are displaced relative to each other. By rigidly fixing the joist to the concrete base, these troubles can be avoided.
Important! If the logs are not firmly fixed, and their humidity stated by the seller does not correspond to reality, then soon, due to the process of warping of the wood, the floor structure will begin to deform and shift.
Proponents of abandoning rigid fastening of joists prefer floating floor designs when the flooring is not fixed to load-bearing structures. In this case, it is necessary to approach the choice of lag material very carefully. The stability of the floating structure will be ensured by the special fastening of the beams to each other - in the form of a lattice, into the voids of which insulating material is placed.
- The process of creating high-quality flooring on joists depends on the correctly selected material. Wood is the most preferred coniferous species, since it resists moisture better, contains natural antiseptics, and is therefore resistant to the formation of fungus, and is also a durable type of wood.
- The moisture content of the timber should not be higher than 18%. Before laying, the timber must undergo an acclimatization period of several days and get used to the microclimatic conditions in the room where it will be used. If during these days some joists begin to show signs of warping, they will be rejected and not used in the floor structure.
- Before laying, logs are treated with an antiseptic and fire retardant. It is better to do this before installation, because it is more convenient to process the entire product.
- It is important to pay attention to the choice of direction for laying the joists relative to sun rays– the beams are laid crosswise to ensure their uniform heating. Where the strength of the flooring is important (in rooms with high traffic), the logs are placed across the movement.
- The distance between the lags is selected in accordance with the thickness of the rough flooring. The larger it is, the greater the distance between the logs (40 - 50 cm). The distance from the wall to the beam should be 2 - 3 cm.
Materials and tools
The work of laying floors on joists does not require specialized equipment and tools. You will need to prepare:
- Hammer drill.
- Screwdrivers or screwdriver, hammer.
- Measuring tools - tape measure, level, pencil.
- Fasteners, depending on the method of fastening.
- Wood processing during work is carried out using a plane, hacksaw or circular saw.
Will need to purchase waterproofing material taking into account the overlap on the walls around the perimeter of the room by no less than 15 - 20 cm.
- You should not take to heart the assurances of lumber sellers that the more expensive and higher the grade of wood, the more reliable and durable the logs made from it will be. For flooring, you can get by with spruce, fir or pine.
- You can safely purchase wood of grades B and BC, provided that its humidity does not exceed 18%. External minor defects and shade of the material can be ignored.
- The main condition is the absence of traces of insect pests (bark beetles) and mold on the surface of the wood - even a minimal amount of it should be a signal to refuse to purchase wood from this batch.
- The cross-section of the beam is selected in accordance with the selected thickness of the flooring and the upcoming loads.
Mounting methods
There are several most common ways to attach joists to concrete. Each of them has its own characteristics.
Fastening joists using self-tapping screws
Although this method of fixing lags is the simplest, it is not suitable in every case. The process is simple:
- A hole is drilled in the concrete base for a plastic dowel.
- A hole for a self-tapping screw is also drilled in the wooden element.
- The dowel is placed in concrete hole, driving with a hammer, and fix the lag, immersing the head of the screw into the body of the wood a few millimeters.
The step taken when attaching the logs in this way is at least 50 cm.
Table 1. Installation of a wooden floor with fastening joists to self-tapping screws
| Illustration | Description |
|---|---|
 | Obvious defects on concrete surface sealed using mortar or foam. |
 | The concrete base is dusted off and debris from this surface is removed using a vacuum cleaner. |
 | The floor is primed with a solution with antiseptic additives. |
 | The logs are pre-treated with antiseptics and fire retardants. |
 | The logs are laid in increments of 50 cm. |
 | Plastic wedges are placed under the joist and with their help the element is adjusted to the desired height. |
 | The height of the logs is controlled using construction corner or tape measure and laser level. |
 | Drill a hole for the self-tapping screw. |
 | Screw in the self-tapping screw. |
 | The wedges must be fixed in the specified position using foam. |
 | |
 | Lay a layer of vapor barrier. |
 | The OSB boards are fixed. |
Fastening joists using anchor bolts
Fixing lags using anchors is a durable and reliable method. Additional rigidity of the structure is provided by attracting the timber to the surface of the base.
An anchor is a more powerful fastener than a dowel; it can withstand high loads. When installing such a floor, you can rest assured that it is securely fixed to the concrete base. According to the technology of work, fastening timber to anchors is similar to fixing it to self-tapping screws. First, holes of the required diameter are drilled in the base and joists. A hole is made in the wood so that the head of the bolt can be hidden.
The number of fasteners is calculated taking into account the fact that an average of 4 anchors are required to fix one beam. The bolt into the locking element, inserted into the hole in the concrete, is driven through the wood. The length of anchor bolts varies from 45 to 200 mm. When choosing it, 6 cm is added to the thickness of the beam for penetration into concrete. Recommended diameter anchor bolt is 10 mm.
The popularity of anchor fastening is due to more rigid fixation wooden structure. With the help of this fastener, you can count on restraining the wood before the deformation process if it has not been sufficiently dried.
Table 2. Anchor installation
| Illustration | Description |
|---|---|
 | After the anchors are driven into the concrete base, using a 13mm wrench you will need to tighten each anchor nut to secure it more securely. However, you should not use too much force to avoid stripping the thread. |
 | After this, a lower nut is screwed onto each anchor and a washer is installed on which the log itself will be laid. The nut is installed reverse side and screw it in, following the markings on the wall. |
 | A puck is placed on top. |
 | A hole is drilled in the joists for the anchor head and under its body, taking into account the spacing of the anchors. |
 | The logs are attached to the anchors. |
 | Screw in the top fixing cap of the anchor. |
 | The nut is tightened in accordance with the level value. |
 | Excess fasteners are cut off using a grinder. |
 | Insulation is laid in the space between the joists. |
 | Sheets of plywood are fixed to the joists. |
Attaching joists using corners
If the height of the logs exceeds 10 cm, then they are used for fastening metal corners. The corner shelf is secured to the concrete base using dowel nails, and to the joist - with self-tapping screws. IN in this case the corner is used to fix the position of the wooden element, and the load is distributed on the spacers.
Table 3. Installation of logs
| Illustration | Description |
|---|---|
 | Before attaching the corner to the joist, drill a hole for the self-tapping screw. To ensure a strong connection, the self-tapping screw is immersed into the wood at an angle. |
 | A hole is drilled in the concrete floor for the dowel. |
 | The dowel is immersed in the hole and the self-tapping screw is screwed in. |
 | A timber is inserted under the logs, which will allow the logs to be fixed to required height and ensure ventilation of the structure. |
 | The bars are also fixed to the floor using corners. |
 | Wooden flooring is made from tongue and groove boards. |
 | To fix the board at an angle, drill a hole for a self-tapping screw. |
 | The board is fixed using a self-tapping screw inserted into the groove at an angle of 45 degrees. |
Adjustable joists
The adjustable joist system is the most in a simple way installation of a level boardwalk in a room with a concrete base that has a significant difference in height. The anchors in this design are replaced with plastic posts, which are attached to the concrete using dowels. The convenience of using plastic racks is that you can adjust their height and the level of the logs using special rotating bolts. Excess posts protruding above the surface of the joists after adjustment are cut off.
Modern manufacturers offer universal racks, which make it possible to produce a perfectly smooth board covering in a room with big difference heights, regardless of the cross-section of the beams. Installation proceeds as follows. The supports are installed on a concrete base.
Lay the logs and, focusing on the level, set the horizontal plane, adjusting the location of the beams using special mechanism racks
Universal racks are equipped with an automatic tilt angle correction system up to 5%.
Adjustable floor - subfloor in the form of joists or plywood flooring
As a rule, flooring in residential premises is laid on a concrete screed and joists. A relatively new option is subfloor construction in the form of logs or plywood flooring, the height of which can be adjusted using special rack blocks. This solution received a quite understandable name - adjustable floor.
Adjustable floor technology involves the use wooden logs or slabs (sheets) moisture resistant plywood 18 mm), which rest on stand-up bolts screwed into them, usually made of high-strength plastic. Turning the bolts around an axis changes the height of the joists or sheets, which allows you to accurately level the subfloor. After leveling the structure, the bolt is rigidly fixed to the base with a dowel-nail. In this case, the base can be either concrete (monolithic, hollow, with a screed) or wooden (beam). Sheets of moisture-resistant plywood are usually laid on top of the logs and any type of floor covering is fixed on them - solid boards, parquet, parquet boards, laminate, linoleum, carpet, etc. In order to save money solid boards sometimes they are mounted directly on the joists.
Advantages of an adjustable floor system
Similar adjustable designs have a number of advantages. First of all, they have advantages over concrete leveling.
- They cost less than concrete screed when leveling a surface with a height difference of more than 3-5 cm.
- There is no need to fuss with cement.
- Installation of adjustable floors be produced much faster pouring concrete screed.
In addition, they allow you to save money and time when installing a base for plank floor coverings (parquet, parquet board, laminate), because concrete preparation in this case it will include not only a screed, but also a self-leveling mixture.
Do not forget also about the need to create waterproofing (and often sound insulation) on top of the screed and a layer of plywood on which it will be laid wood covering. In total, the costs of such preparation will be higher than the costs of installing an adjustable structure.
Another important point: Installation of adjustable joists typically takes less than a week, as one worker installs an average of 20-25 m² of adjustable joists or slabs per day. A completely different situation with a base made of concrete screed: for carrying out parquet work its strength must be at least 150 kg/cm², and the screed acquires such strength within 28 days. However, this time period is not enough to start laying parquet or boards.
Note that European standards require drying the screed to 3-4%. It is a mistake to assume that it dries to this level in 28 days: this process takes longer than the curing process and usually takes several months.
There is no direct contact in the design of adjustable supports wooden elements with the base of the floor, and, therefore, you can lay logs on top of the concrete floor, and then plywood and parquet without waiting for the concrete to dry completely. In case of overlapping with high humidity, lay on it plastic film, cutting off water vapor, after which the installation of logs or slabs immediately begins.
Finally, the adjustable floor design offers the possibility air movement under the floor and thereby removing excess water vapor, which can lead to warping and rotting of the wood. The supply and exhaust of air is carried out due to the gaps between the floor and the wall of the room (there is also a gap between the baseboard fixed to the wall and the floor). The standard value of this gap is 10 mm. If you need to improve the ventilation of the space under the subfloor, you can install it in the floor in opposite corners of the room decorative grilles for additional air supply and exhaust.
Another advantage of adjustable structures is that they improve sound insulation of the room: the floor is not monolithic, but contains in its “pie” air gap. If necessary, increase the level of sound or thermal insulation of the floor (for example, in a home theater or ground floor) it is possible to lay slabs from mineral wool between the lags. In addition, plastic racks dampen the noise.
Adjustable floor slabs are laid on metal plates fixed to joists. The thickness of the insulating layer can be varied, but there is usually no contact between the slabs and the concrete base (they are separated by an air gap), so in the case high humidity the ceiling insulation will remain dry.
Next point: height-adjustable floors allow laying under floor covering engineering Communication (pipes with a diameter of up to 100 mm) and any wiring. Moreover, communications will take the shortest path, so there will be fewer connecting nodes, therefore, the reliability of the system will increase, and the cost of its installation, on the contrary, will decrease.
Adjustable floors on joists or plywood boards have obvious advantages before concrete leveling, if we are not talking about abstract “ concrete screed", but about the base for parquet, parquet boards or laminate, which includes layer, layer and layer. Adjustable structures are cheaper than such a base, especially when it is necessary to level a floor with large differences in height.
In addition, it gains strength within 28 days, while installation of an adjustable floor usually takes from 2-3 days to a week. In addition, utilities and wiring can be laid under the adjustable floor, and, if necessary, heat and sound insulation slabs. However, such a floor itself increases the sound insulation of the room due to air cushion between the floor covering and the ceiling, as well as through the use of plastic post bolts.
Problems and disadvantages of adjustable floors
One of the problems that arise when using a wooden floor is creak. Is there a possibility of it appearing in floors along adjustable joists or slabs? Experts say that with high-quality installation of the system there will be no squeaking. It can occur when the floor elements do not fit tightly together, for example, when improper fastening bolts to the base or improper formation of gaps between the end joints of the joists and plywood. However, with qualified installation, all elements of the system are so rigidly fixed to the base and interconnected that even a slight drying of the wood, according to experts, will not result in a creaking floor.
However, There may be a knock on the floor, if the concrete base on which the logs rest is made with errors: for example, if the screed applied to the ceiling crumbles or cracks. Then it is recommended to remove the bad screed before installing the floor, and also select the correct dowel-nail model for attaching the bolt to the base.
Poor cleaning of dust when installing adjustable structures leads to dust particles getting into the gaps, which can lead to creaking in the floor.
Let us add that the maximum permissible pressure for adjustable structures can reach 3 tons per 1 m², which corresponds to a large margin of safety for the floor. Their estimated service life is at least 50 years.
Another possible (not everyone even notices it) disadvantages of adjustable floors can be called a kind of hum when moving along them, especially if the shoes have high heels or the soles are very hard. This is especially evident if you jump on such a floor.
Installation of adjustable floors
If it is necessary to raise the floor by 50 mm or more, install adjustable joist design. And if the required lifting height is from 30 to 50 mm, use system of adjustable boards (plywood).
Adjustable joist system (adjustable floor on joists).
When installing the floor on concrete floor Most often, logs with a cross section of 45 x 45 mm and a length of 2 or 3 m are used. Their standard pitch is 300 mm between the axes of the bars. When laying the floor on a ceiling made of wooden beams usually logs with a larger cross-section are required; its size is selected taking into account the pitch of the beams (as a rule, logs with a cross-section of 45 x 70 mm are used). You can also vary the lag pitch. For each lag there are 5 stand-up bolts with a diameter of 28 mm, for which threaded holes are prepared at the factory.
The length of the bolts is usually 100 or 150 mm: it is chosen depending on the height to which the floor needs to be raised. The installation of the structure begins with bolts being screwed into the logs, then the logs are laid out on the base with the required pitch and holes for dowel-nails are marked. Moreover, a gap of about 10 mm is left between the logs and the walls.
First, bolts are screwed into the logs, after which they are laid out on the base, marking and then drilling holes for dowel-nails
Alignment of the lags is carried out using a level and a hex wrench
Then they begin to level the joists by rotating the bolts with a hex wrench (the bolts have a hex groove), using a level.
The height of the plastic bolts is adjusted using a special hex key
Having completed the alignment, the dowels are driven all the way into the base, and the protruding part of the plastic bolt is cut off flush with a chisel.
After leveling the joists, the dowels are driven all the way into the base
Then the plywood flooring is installed. According to the recommendations of system manufacturers, the thickness of the flooring should be at least 18 mm. However, many experts recommend making flooring up to 30 mm thick with a lag pitch of 300 mm under parquet and solid boards.
As a rule, two layers of plywood sheets are laid (with the top sheet overlapping the junction of the two lower ones) to ensure maximum structural rigidity. As a rule, layers of plywood are fastened with self-tapping screws, but experts increasingly recommend that in addition to this, they must be glued upper layer to the bottom. The flooring is installed on top of the plywood.
Let us add that there are other adjustable designs on the market. In particular, systems where metal stand-up bolts (anchors) are used, and adjustment occurs using a nut screwed onto them with a support washer.
There are also systems with U-shaped metal brackets that “clasp” the lag from the sides and are secured to it with self-tapping screws. The bracket is provided with a number of holes, and after alignment, the screws are screwed into holes of suitable height.
The reliability of the floor structure with adjustable joists is achieved due to the right choice section and pitch of the lag in combination with the thickness of the subfloor, as well as due to high-quality installation. In a standard situation, the pitch of a lag with a section of 45 x 45 mm should be 300 mm with a subfloor thickness of 30 mm (usually two layers of plywood with sheet thicknesses of 18 and 12 mm). Layers of plywood should be glued together to achieve maximum structural rigidity.
There is an exception: if you use parquet board fixed to the base with glue, it is enough to lay one layer of 18 mm plywood, since such a board and plywood have the same size thermal expansion, and the rigidity of the structure is beyond doubt. The cross-section and pitch of the joists change, as a rule, when the floor is laid on top of a floor made of wooden beams. The distance between the beams can be quite large (1 m or more), so you have to either increase the section of the logs, or install the logs with smaller pitches and increase the thickness of the two-layer flooring - made of plywood or a combination of tongue-and-groove boards and plywood.
The price of components for adjustable floor structures starts from 400 rubles/m². Adjustable plywood floor installation kit
Adjustable slab system (adjustable plywood floor).
The technology for installing an adjustable plywood floor is somewhat different. A hole is drilled in the plywood into which a plastic sleeve with a diameter of 60 mm, having a threaded hole, is inserted. The sleeve is secured to the joist or plywood with self-tapping screws. Then the post bolt is screwed into the bushing, after which the entire cycle of the work listed above is performed.
Technology for constructing a system of adjustable slabs (plywood):
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1. Drilling holes in plywood and fixing plastic bushings with self-tapping screws; |
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2. Screwing the post bolts into the bushings |
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3. Fastening the stand-bolts with metal dowel-nails to the base |